Visiting the machine shop tomorrow

[gettin'even]

Re: Visiting the machine shop tomorrow

This is EXACTLY what I was talking about reading the new guys posts.

The 470 has absoluteley nothing to do with GM specs.
It's NOT a GM engine, it's a Mercruiser Aluminum block with an Open Deck design, using a Ford 460 head and valve train.

Phew...thought you were looking at me when you first said "new guy".....



On a serious note....

I still to have found where the "470" nomenclature came from. Does anyone know?

 

[dr_bowtie]

Re: Visiting the machine shop tomorrow

.though I'm not sure why with the full dish auto pistons.

the dish is meant to control the flame front...the Quench creates the turbulance needed to keep the gasses in the center thus making proper combustion possible...

unlike domed pistons where the flames front chases itself around the piston at times causing an incomplete burn...

dish have a larger margin for complete burn to happen more easily...

 

[sdoomaha]

Re: Visiting the machine shop tomorrow

Good Luck Nate. I rebuilt mine about 4 years ago...I'm shadetree...with your experience you'll be fine.

I was told the 470 name came from the 170 horsepower out of a 4 cylinder motor. There is also the 488 which is the 4 barrel 188 horse version of the same motor. Don;t know if it is true...but seems logical.

Take care.

 

[natemoore]

Re: Visiting the machine shop tomorrow

Guys,
We're on the verge of making this the best 470 rebuild discussion in the history of the internet! Yeah! iboats! iboats! iboats!......

What would we do without internet forums like this? Imagine how much harder it would be to gather information.

I really appreciate all the information, including the "whamp whah whah whamp whah whah whahs". I'll have a long list of things to discuss with my machine shop guy.

 

[natemoore]

Re: Visiting the machine shop tomorrow

that would be correct...

for those pistons I cut the top ring at .022
and the 2nd ring at .018

but you might ask the machine shop that does your work what they think...

I have run up to .030 on the top and up to .022 on the 2nd on some that ran hard at 6000rpm....

either that or get Total Seal rings for Hyper pistons...

I found a website that sells Quicksilver pistons Part # 759-806661A7 for $105 each (out of stock), so I assume the are new, old stock. The description says they are hypereutectic cast aluminum.

So if I put in the hypereutectic pistons from Speed Pro, I can probably stay with the Mercruiser specs? They are are .010-.020 for the top two compression rings, and .010-.025 for the oil rings.

Were you thinking that the OEMs were not hyper? Are the Speed-Pro piston extra-super-hyper? Or are you just recommending an additional safety factor? Would you be comfortable if I filed to the upper limit of .020?

 

[natemoore]

Re: Visiting the machine shop tomorrow

Crap! Is it worth an extra $100 for the Quicksilver overhaul gasket set???

Am I going to open my expensive Quicksilver set and see a "Victor" stamp on the head gasket?

Will I open my cheaper Sierra set and see the same "Victor" stamp on that head gasket?

Does anyone know for sure???

 

[bruceb58]

Re: Visiting the machine shop tomorrow

I still to have found where the "470" nomenclature came from. Does anyone know?

The original designer was smoking and got 420 mixed up with 470.

 

[dr_bowtie]

Re: Visiting the machine shop tomorrow

I found a website that sells Quicksilver pistons Part # 759-806661A7 for $105 each (out of stock), so I assume the are new, old stock. The description says they are hypereutectic cast aluminum.

So if I put in the hypereutectic pistons from Speed Pro, I can probably stay with the Mercruiser specs? They are are .010-.020 for the top two compression rings, and .010-.025 for the oil rings.

Were you thinking that the OEMs were not hyper? Are the Speed-Pro piston extra-super-hyper? Or are you just recommending an additional safety factor? Would you be comfortable if I filed to the upper limit of .020?

I would think as old as the motor is that it has cast pistons...for OEM...just because it says Cast doent mean they are or arent Hyper pistons...

.010-.020 is normal ring end gap for cast pistons....Hyper pistons need about .010 more than cast pistons...

Just pay attention to what you get and set the rings accordingly....cast are fine and are good up to 6,000rpm before they start to crystallize...

I have run cast pistons in peanut motors upwards of 8500rpm and have never lost one but you are only doing it for 12 seconds at a time or less so it aint much stress...not like a bout where it may spend a large amount of time at the higher limit...

Hyper pistons are right in between cast and forged...and they take quite a bit of abuse...

 

[erikgreen]

Re: Visiting the machine shop tomorrow

Who cares about running above 4800 RPM? The drive won't deal with that RPM even if the engine will, and you won't get much benefit anyway, since your boat mostly needs more torque, not more RPM.

As Don said, you're not building a race engine. Just build it to marine standard and you'll be happy. Build it to super tight race ready tolerances if you like, but you're only going to get a couple mph more at the cost of a lot of fuel and shorter engine life... which should be a concern if you're running a 470, I would think. Replacing major parts won't be cheap.

Just get the mercruiser manual for the 470 and follow the specs there for clearances and such. Spend what you like on "special" parts, but you won't get much for doing that except satisfaction and shiny bits in the engine.



Erik

 

[natemoore]

Re: Visiting the machine shop tomorrow

Who cares about running above 4800 RPM? The drive won't deal with that RPM even if the engine will, and you won't get much benefit anyway, since your boat mostly needs more torque, not more RPM.

As Don said, you're not building a race engine. Just build it to marine standard and you'll be happy. Build it to super tight race ready tolerances if you like, but you're only going to get a couple mph more at the cost of a lot of fuel and shorter engine life... which should be a concern if you're running a 470, I would think. Replacing major parts won't be cheap.

Just get the mercruiser manual for the 470 and follow the specs there for clearances and such. Spend what you like on "special" parts, but you won't get much for doing that except satisfaction and shiny bits in the engine.



Erik

Yeah, if run in Santa Rosa Sound at WOT, I risk bouncing myself, my wife, and two kids out of the boat. I usually putter about at about 3800-4000 rpms. That is a comfortable speed for us.

I'm not interested in building to racing specs, but I've enjoyed learning about all that stuff.

 

[Bifflefan]

Re: Visiting the machine shop tomorrow

The 470 has absoluteley nothing to do with GM specs.
It's NOT a GM engine, it's a Mercruiser Aluminum block with an Open Deck design, using a Ford 460 head and valve train.

Got to love that... only the best parts in there....
Aluminum and Ford... nothing better....

 

[natemoore]

Re: Visiting the machine shop tomorrow

Got to love that... only the best parts in there....
Aluminum and Ford... nothing better....

At least Ford can pay its bills

 

[sockos]

Re: Visiting the machine shop tomorrow

I've never built a 470 marine engine, but I have built 2 Clevelands and one 460 car engine. As I recall the dished ( ashtray or bathtub) pistons came out at 8.5:1 compression , and just upping stock bore pistons to flat tops jump it to 10.25:1. Tough to run on pump gas.
The trouble came when decking heads and blocks since the valve train is non adjustable. The 460 that I built needed custom pushrods to offset the loss in height from machining.
I'm not sure if the marine 460 head has kept the same torque and forget rocker set up. Be kinda nice to know just for my semi useful facts locker.

 

[natemoore]

Re: Visiting the machine shop tomorrow

I've never built a 470 marine engine, but I have built 2 Clevelands and one 460 car engine. As I recall the dished ( ashtray or bathtub) pistons came out at 8.5:1 compression , and just upping stock bore pistons to flat tops jump it to 10.25:1. Tough to run on pump gas.
The trouble came when decking heads and blocks since the valve train is non adjustable. The 460 that I built needed custom pushrods to offset the loss in height from machining.
I'm not sure if the marine 460 head has kept the same torque and forget rocker set up. Be kinda nice to know just for my semi useful facts locker.

I guess they're torque and forget, but you have to make sure you have the proper valve clearance, and if it's off, like you, I'll have to order pushrods of different lengths.

 

[jtybt]

Re: Visiting the machine shop tomorrow

Sorry Don,
I forgot we were talking about the 470. BUT in general, specs are the same as the engine manufacturer. Since the 470 was a merc design, their specs are the guide.

The original 470 had an iron block, though.

I may be new to your site but I'm far from a beginner.

 

[stonyloam]

Re: Visiting the machine shop tomorrow

Been away for a week. My! Things have gotten interesting! Forget the transplant! Why add 200 pounds of useless iron to the stern of your boat with a wornout (probably cracked) 4.3 or a wimpy little 4 cyl. from a junk boat? Sounds like you are doing everything right, go for it! But watch out it will probably only kick butt for the next 20 years or so. Remember the 470 was designed as a MARINE engine not a car engine. Have fun! BTW I think it would be wise to use the Merceuiser OEM head gasket, aftermarker would probably be fine for all the others.

 

[Bt Doctur]

Re: Visiting the machine shop tomorrow

Red 67502-3 8.595-8.625
Blue 67502T 8.655-8.685
No color 67502T-1 8.625-8.655
Yellow 67502T-2 8.865-8.715

 

[natemoore]

Re: Visiting the machine shop tomorrow

Red 67502-3 8.595-8.625
Blue 67502T 8.655-8.685
No color 67502T-1 8.625-8.655
Yellow 67502T-2 8.865-8.715

These look like pushrod lengths and part numbers.

 

[stonyloam]

Re: Visiting the machine shop tomorrow

These look like pushrod lengths and part numbers.

They are. From the "book", page A3-10 & 11 "valve clearance is not adjustable. If clearance is not correct it will be necessary to change the pushrod length so proper clearance can be achieved." The manual tells you how to measure it.

 

[natemoore]

Re: Visiting the machine shop tomorrow

They are. From the "book", page A3-10 & 11 "valve clearance is not adjustable. If clearance is not correct it will be necessary to change the pushrod length so proper clearance can be achieved." The manual tells you how to measure it.

I know. I don't remember anyone asking about/mentioning valve clearance. I do remember someone mentioning bearing clearance, and saying that if I wasn't familiar with it, the machine shop would do it for a small fee. I thought it was kind of a random post. Oh well, never can have too much information.